Issues an error if the children do not
all have the same parent or if the parent is not a subclass of compositeWidgetClass.

·

Returns immediately if the common parent is being destroyed; otherwise,
for each unique child on the list, XtManageChildren ignores the child
if it already is managed or is being destroyed and marks it if not.

·

If the
parent is realized and after all children have been marked, it makes some
of the newly managed children viewable:

-

Calls the change_managed routine
of the widgets' parent.

-

Calls XtRealizeWidget on each previously unmanaged
child that is unrealized.

-

Maps each previously unmanaged child that has
map_when_managed True.

Managing children is independent of the ordering
of children and independent of creating and deleting children. The layout
routine of the parent should consider children whose managed field is True
and should ignore all other children. Note that some composite widgets,
especially fixed boxes, call XtManageChild from their insert_child procedure.

If the parent widget is realized, its change_managed procedure is called
to notify it that its set of managed children has changed. The parent can
reposition and resize any of its children. It moves each child as needed
by calling XtMoveWidget, which first updates the x and y fields and
then calls XMoveWindow if the widget is realized.

The XtManageChild
function constructs a WidgetList of length one and calls XtManageChildren.

The XtUnmanageChildren function performs the following:

·

Issues an error
if the children do not all have the same parent or if the parent is not
a subclass of compositeWidgetClass.

·

Returns immediately if the common
parent is being destroyed; otherwise, for each unique child on the list,
XtUnmanageChildren performs the following:

-

Ignores the child if it already
is unmanaged or is being destroyed and marks it if not.

-

If the child is
realized, it makes it nonvisible by unmapping it.

·

Calls the change_managed
routine of the widgets' parent after all children have been marked if the
parent is realized.

XtUnmanageChildren does not destroy the children widgets.
Removing widgets from a parent's managed set is often a temporary banishment,
and, some time later, you may manage the children again.

The XtUnmanageChild
function constructs a widget list of length one and calls XtUnmanageChildren.

The XtChangeManagedSet function performs the following:

·

Issues an error
if the widgets specified in the manage_children and the unmanage_children
lists to no all have the same parent, or if that parent is not a subclass
of compositeWidgetClass.

·

Returns immediately if the common parent is being
destroyed.

·

If no CompositeClassExtension is defined, or a CompositeClassExtension
is defined but with an allows_change_managed_set field with a value of
False, and XtChangeManagedSet was invoked with a non-NULL post_unmanage_pre_manage_hook
procedure then XtChangeManagedSet performs the following:

Otherwise, if a CompositeClassExtension
is defined with an allows_change_managed_set field with a value of True,
or if no CompositeClassExtension is defined, and XtChangeManagedSetwas
post_unmanage_pre_manage_hook procedure, then the following is performed:

-

For each child on the unmanage_children list; if the child is already unmanaged
or is being destroyed it is ignored, otherwise it is marked as being unmanaged
and if it is realized it is made nonvisible by being unmapped.

-

If the post_unmanage_pre_manage_hook
procdedure is non-NULL then it is invoked as specified.

-

For each child on
the manage_children list; if the child is already managed or it is being
destroyed it is ignored,

otherwise it is marked as managed

·

If the parent
is realized and after all children have been marked, the change_managed
method of the parent is invoked and subsequently some of the newly managed
children are made viewable by:

-

Calling XtRealizeWidget on each of the
previously unmanaged child that is unrealized.

-

Mapping each previously unmanaged
child that has map_when_managedTrue.

The XtIsManaged function returns
True if the specified widget is of class RectObj or any subclass thereof
and is managed, or False otherwise.